归档空间使用率达到90时，及时清理脚本

应对归档突增情况，当达到90%时就强制删除（只保留最近20个）

#!/bin/bash
# clear older archivelog when archive file space used% > 90
# crontab example: */5 * * * * sh /home/oracle/scripts/clear_arch.sh

. ~/.bash_profile
# .~/.profile

# get arch space used

getArchUsed(){
sqlplus -S "/as sysdba" <<EOF
set head off
set feedback off
set time off
set timing off
set echo off
select round((total_mb-free_mb)/total_mb*100,2) used_percent from v\$asm_diskgroup where name ='ARCHDG';
exit
EOF
}
archUsed=$(getArchUsed)

# export arch_dest='/home/ora/fast_recovery_area'
# archUsed=` df -P $arch_dest |grep /|awk '{print $5}'|sed 's/\%//g' `

if [ "${archUsed}" < 90 ]; then
exit
fi

getsql(){
sqlplus -S "/as sysdba" <<EOF
set head off
set feedback off
set time off
set timing off
set echo off
select 'delete force noprompt archivelog from sequence 0 until sequence '||max(sequence# - 20)|| ' thread ' || thread# ||';'
  from v\$archived_log group by thread#;
exit
EOF
}

delOldArch(){
sql=$(getsql)
echo "begin deleting standby archivelog"
rman target / log=${logfile} append <<EOF
$sql
exit;
EOF
}

getrole() {
sqlplus -S "/as sysdba" <<EOF
set head off
set feedback off
set echo off
set time off
set timing off
select database_role from v\$database;
exit
EOF
}

role=$(getrole)
role=`echo ${role} |sed 's/ //g'`
echo $role
if [ "${role}" = "PRIMARY" ]; then
delOldArch;
else
echo "error, unable to connect to the database, try again later"
fi

Good Luck！